Chapter 3 Digestion, Absorption, and Transports3.amazonaws.com/prealliance_oneclass_sample/roVRBea0vJ.pdf · Diseases involving carbohydrate metabolism ... the breakdown of some carbohydrates

Enriched Instructor’s Manual to Accompany Understanding Nutrition, First Canadian Edition 3-1

Chapter 3Digestion, Absorption, and Transport

I F N O T H I N G E L S E , M Y S T U D E N T S S H O U L D L E A R N …

1. That the gastrointestinal tract is a flexible muscular tube that digests (i.e., breaks down) nutrients for absorption into the lymphatic and cardiovascular systems. It is important to know the names and location of all of the parts that make up the digestive system (both digestive and accessory organs) and their role in digestion.

2. That the functioning of the gastrointestinal (GI) system is regulated by the endocrine and nervous systems.

3. That the gastrointestinal system uses different mechanisms to absorb macro and micronutrients.

L E A R N I N G O B J E C T I V E S

Students should be able to:

• LO 3.1: Describe the levels of organization in the body and identify some basic ways in which nutrition supports them. [Understand/Apply]

• LO 3.2: Define the terms mechanical digestion and chemical digestion and point out where these processes occur along the digestive tract. [Remember/Understand]

• LO 3.3: Trace the breakdown and absorption of carbohydrate, fat, and protein from the mouth to the colon. [Remember/Understand]

• LO 3.4: Explain how nutrients are transported and stored in the body. [Understand]

• LO 3.5: List the five organs and their secretions that assist in the breakdown of food. [Understand/Apply]

• LO 3.6: List the secretions that break down carbohydrates, protein, and lipids. [Remember/Understand]

• LO 3.7: Describe the anatomy and mechanisms of nutrient absorption from the gastrointestinal system to the lymphatic and cardiovascular systems. [Remember/Understand]

Copyright © 2013 by Nelson Education Ltd.


• LO 3.8: Identify the hormones involved in digestive and absorptive processes. [Understand]

• LO 3.9: Apply the concepts presented in the chapter to explain common digestive tract problems. [Understand]

W H Y I S T H I S C H A P T E R I M P O R T A N T T O S C I E N T I S T S A N D H E A L T H C A R E P R A C T I T I O N E R S ?

“Of special interest to...” symbol key: = HealthCare Practitioners = Science Majors

• The functioning of all body cells is dependent upon the energy provided by the macronutrients (i.e., carbohydrates, protein, and lipids) and oxygen. The provision of micronutrients in the food we eat enables the body’s cells to harness the stored chemical energy in the macronutrients. A cell’s genes control the type of work that is done by each cell by making new protein, provided that the diet supplies the body with a source of the protein’s building blocks (i.e., amino acids).

• Scientists have discovered many dietary factors influence the development and/or progression of various diseases. Diseases involving carbohydrate metabolism (e.g., diabetes mellitus) are significantly affected by the quality of the carbohydrate ingested as part of the diet. For example, socalled “good carbs” and “bad carbs” both provide the necessary glucose molecules for the body’s energy needs, yet the type of carb plays an important role in the body’s response to those macronutrients. The healthcare practitioner will often recommend to patients to follow a mixed diet that includes complex carbohydrates and fibre in order to generate a more stable blood glucose level while minimizing drastic fluctuations in insulin.

• The effectiveness of highprotein diets in weight loss/management has led many scientists to investigate how protein ingestion quantity, quality, and timing may contribute to human health and fitness. Healthcare practitioners have also realized that ingesting a highquality protein immediately following bouts of exercise leads to a level of positive protein balance by stimulating protein synthesis.

• Understanding how the body absorbs lipids and lipidsoluble dietary items (i.e., fatsoluble vitamins) has provided important guidelines for consuming various types of fats that would either increase or decrease risk factors for cardiovascular disease. The healthcare practitioner should develop an understanding of lipid absorption in order to counsel future patients on the negative effects of a diet high in fats.



W H Y S H O U L D S T U D E N T S C A R E ?

• Students should understand that in order to harness the stored chemical energy in food (macronutrients) as well as vitamins and minerals, the digestive system doesn’t work in isolation. The digestive system is able to accomplish its tasks with optimal functioning of the cardiovascular, lymphatic, nervous, and endocrine systems. As an example, describe how some students experience the postlunch “crash” in their afternoon classes. This can be attributed, in part, to the ingestion of a lunch containing carbohydrates that eventually gets broken down into glucose (and other monosaccharide) units, moves into the bloodstream, and then exits the bloodstream as they are put into storage.

• Students need to know that cells are organized into tissues that perform specialized tasks. Tissues are grouped together to form whole organs. Some body functions are performed by having several related organs (e.g., the stomach, small and large intestine) work together as part of a body system (e.g., the gastrointestinal system).

• In order to deliver the macro and micronutrients to the cells throughout the body, various enzymes act on the food that we eat. Understanding the actions of various enzymes will help students to appreciate the need of the digestive system to break down the food we eat into “manageable molecules” so that they can be absorbed into the cardiovascular and lymphatic systems. A general class of enzymes, referred to as the amylases, function to break down dietary carbohydrates so that glucose can be absorbed. As a thoughtexercise, ask students what would happen if this enzyme was not present in gastrointestinal secretions? Would we be able to break down dietary carbohydrates to glucose? If not, then we would not be able to absorb these important energy molecules for our cells.

• Students should know that the nervous and hormonal systems regulate activity of the digestive system. Together, the hormonal and nervous systems respond to the need for food, govern the act of eating, regulate digestion, and induce a stress response. As an example, have students recall a situation when they went out for dinner at a restaurant after a long day of class. As they are waiting for their food, the server passes by them with a plate of their favourite order for another table. The sight and smell of that food through the students’ senses will activate pleasurable memories of eating that food. The students may likely feel (or hear) stomach rumbling or start secreting small amount of saliva without eating anything. This is the branch of the autonomic nervous system initiating digestive secretions, illustrating the powerful effect of this system in regulating digestion.

• The gastrointestinal tract accomplishes the breakdown of food by the action of the ancillary digestive organs (i.e., salivary glands, liver, gallbladder, and pancreas). Students should understand that the ingestion of certain foods (e.g., those high in lipids) will trigger hormonal/nervous responses that cause these ancillary organs to secrete enzymes that leads to macronutrient catabolism. For this reason,



scientists interested in studying gall bladder function will often feed research participants a highfat cream beverage. The fat content will stimulate the small intestine to secrete a hormone (cholecystokinin), which will trigger the gall bladder to contract and “pump” bile into the digestive system to help break down the lipid molecules.

• Food undergoes two types of digestive processes: mechanical and chemical digestion. Students should be able to compare and contrast these two processes, providing examples. The mechanical aspect of digestion involves the movement of food through the digestive system—through its various processing chambers by mechanical means. The mechanical actions include chewing, mixing by the stomach, adding fluid, and moving the tract’s contents by peristalsis. After digestion and absorption, wastes are excreted.

• Chemical digestion begins in the mouth, where food is mixed with an enzyme (amylase) in saliva that acts on carbohydrates. Digestion continues in the stomach, where stomach enzymes and acid break down protein. Digestion then continues in the small intestine; there, the liver and gallbladder contribute bile that emulsifies fat, and the pancreas and small intestine donate enzymes that continues digestion so that absorption can occur. Bacteria in the colon breaks down certain fibres; however, most dietary fibre is not digestible. This is of particular importance for students to know if, for example, they have a diet that is very high in dietary fibre. We know that dietary fibre contributes to maintaining digestive system health, but too much will interfere with absorption of other important micro and macronutrients and could potentially lead to dietary deficiencies. This is a good example of practising moderation and variety in one's diet.

• The ability of the digestive system to absorb the nutrients contained in the food we eat comes from the presence of numerous folds within the gastrointestinal wall and the microvilli, which increases the internal surface area over which absorption can take place. Students should understand that this anatomical fact maximizes the body’s ability to obtain the nutrients and energy it needs to function.

• The student should understand that a healthy digestive system may contain up to 400 different species of bacteria that helps to promote health. Certain foods, such as yogurt, help to promote the activity of these bacteria which are necessary for the breakdown of some carbohydrates (through fermentation), as well as produce a range of vitamins. This is why numerous companies who manufacture/sell yogurt products advertise the inclusion of “probiotics” and/or “prebiotics,” as these food items contain bacteria that are incorporated into the digestive system.

• Following the ingestion of food in which it is digested and absorbed, it is important to note that the nutrients are utilized by cells for a variety of purposes (for example, protein synthesis, energy pathways, supporting blood clotting). Macro and micronutrients that are not readily utilized are stored, depending on the nutrient. Storage depots for carbohydrates include muscle and liver cells (in limited quantities). The type of lipid that is used as an energy substrate (fatty



acids) is stored as triglycerides within adipocytes that are distributed throughout the body in adipose tissue. It is important for the student to realize that there is no central storage location of amino acids as they are constituted into proteins.

W H A T A R E C O M M O N S T U D E N T M I S C O N C E P T I O N S / S T U M B L I N G B L O C K S ?

1. To begin study of the anatomy and physiology of the digestive system, students should attempt to envision the travel of food through the entire digestive system much like driving their car (or riding their bike) from point A to B. This approach will help students remember the anatomical distinctions of the digestive system without having to use “brute force” memorization.

2. Students often have difficulty comprehending how long the small intestine actually is and how it is packaged into the abdominal region.

3. Energy metabolism is often a confusing topic to students. It is suggested that a basic equation describing energy handling of the body first be presented and used as a basis for what the body does with the food we eat: EIN = EOUT + ESTORED. The EIN refers to the energy contained in the food we eat, EOUT refers to energy expended (basal metabolic rate at rest, the metabolic activity associated with food digestion/absorption, and any increases in metabolism above resting levels), and ESTORED refers to the protein, lipids, and carbohydrates stored in various tissues.

4. When it comes to hormones (other other molecules for that matter), students often have difficulty appreciating their importance. It is recommended that a depiction of the molecule be presented to students (i.e., chemical structure) so that they can understand that we’re dealing with a physical entity that will attack a particular food item or bind to the membrane of a cell.

5. Using diagrams of protein transporters and membrane structure will help students to visualize how macro and micronutrients are absorbed. Focusing on the individual constituents of macronutrients (i.e., monosaccharides, amino acids, and fatty acids/glycerol) will enable students to draw a path of these molecules from the gastrointestinal system, through the cardiovascular system, and finally, into a metabolic pathway.

W H A T C A N I D O I N C L A S S ?

There are a variety of activities that can be done in class. Listed below are some activities that will help introduce the topic of nutrition, and the students to each other.



Classroom Activity 31: ChapterOpening QuizAs a way of introducing any new chapter, give a quiz to the class. This is a quiz designed to be projected on an overhead projector. For details, please see Chapter 1, Classroom Activity 14.

Classroom Activity 32: Demonstration of the Digestive SystemCoil a 3metre (10foot) rope, hose, or tube in a small bag. Pull the rope out of the bag and instruct the students to guess how long the small intestine is. Have the students pass the rope down the rows of the classroom until the full rope is exposed.

Classroom Activity 33: Evaluation of Products for Digestive ProblemsHave students bring overthecounter products designed to treat common digestive problems (heartburn, constipation, diarrhea, hemorrhoids). Discuss the appropriate and inappropriate uses of these medications and adverse health implications associated with misuse and overuse of certain medications. For example, overuse of medications for heartburn may foster a basic environment in the stomach and therefore hinder iron absorption. You also can discuss alternative solutions to other common digestive problems discussed in Highlight 3.

Classroom Activity 34: Crossword Puzzle by Mary A. Wyandt, Ph.D., CHESDistribute Worksheet 32 and instruct students to complete the crossword puzzle. The answer is provided in the Answer Key.

Classroom Activity 35: “Who Wants to Be a Millionaire?” as a Tool for Review (and Fun)1

Materials needed: Computer projection system; Microsoft PowerPoint with animation and sound effects, plus review questions on PowerPoint slides; overhead projector; chair and table; index cards; hat or jar

Setup: A computer projection system is used for the questions and an overhead projector for the point scale. The room is set up with a chair facing a table, which faces the projection screen. The student selected to play sits in the chair and has the three lifelines taped to the edge of the table. Once a student uses that lifeline, it is flipped over.

How To Play: Selection of the student to play begins with the “fast finger” round. Every student receives an index card. The question may relate specifically to the subject matter or may be something like university trivia. The question is shown on the screen and students have approximately 10–20 seconds to write down their answers. The correct answer is then shown and every student who answers correctly puts the index card in a hat or jar. One name is then randomly selected to play. The play then follows the format of the television game. The lifelines are Ask the Audience (take a class vote on the possible answers), 50/50 (take away two of the wrong answers), and Phone a Friend (ask anyone in the classroom). The point scale (see below) shows the levels of bonus points to be added to the upcoming exam. If a student becomes a millionaire, he or she receives 100 points (the value of the test).

1 Activity provided by Dr. Inza Fort and Dr. Ro Di Brezzo, University of Arkansas



Student Reaction: Student comments have been very positive. It helps them review material and they have really enjoyed the game and the effort put into its construction. There is a lot of encouragement from the class for the student player. A few students in different semesters became “Millionaires” and the class cheered for them!

Comments: Although the initial construction was quite time consuming, once a set is done with the animation and sound effects, the file can be copied and new questions substituted.

Point Scale:100 pts.2520151210 pts.98765 pts.4321

Critical Thinking Questions2

These questions will also be posted to the book’s website so that students can complete them online and email their answers to you.

1. Chapter 3 describes in detail how food is processed for use by our bodies. Over your lifetime, you have come into contact or heard about the following medical issues: painful and bleeding mouth ulcers; stomach cancer; and gallbladder surgery and removal. To the best of your ability, use the information in Chapter 3 to describe the types of nutritional and food intake issues that your patient might face with one of these medical/physiological problems. Can you propose some nutrition therapy alternatives?

2. The process of food digestion through the gastrointestinal tract involves an intricate symphony of interplay between many systems. A breakdown within any system will influence a patient’s ability to absorb nutrients or eliminate waste. Discuss your concerns as a patient’s nutrition expert (RD) if one of the following systems is dysfunctional: vascular system or absorptive system.

3. In this chapter, the concept of homeostasis is discussed in relation to the process of digestion. Describe homeostasis and then discuss the variety of systems that are part

2 Contributed by Kathleen Rourke.



of the digestive homeostatic process. What is another term that is used for the types of regulation that occur when these systems work together to regulate digestion in the GI tract?

4. In general, we often think that bacteria on or in the body is a “bad” thing. However, we normally retain bacteria in the intestine for specific reasons. Provide a short discussion of the functions of these bacteria. How can our dietary intake support the functions of the intestinal bacteria?

5. After studying the GI system in Chapter 3, you can appreciate how complex and well organized this system is as a whole, and how well it functions in digesting and absorbing the food we eat to allow it to be used for energy, metabolic reactions, tissue growth, and repair. We have discussed some of the ways that the GI system may break down and impact nutrient absorption and use. However, even in a healthy individual, there are many factors that can optimize the functioning of the GI system, and therefore nutrient digestion, absorption, and use. Discuss some of the factors that you would assess in healthy patients who came to you concerned about maximizing their nutritional status and nutrient absorption.

6. Highlight 3 suggests many common and simple solutions to common digestive problems. These problems are quite often observed by healthcare professionals in the course of caring for patients in a hospital or clinic setting. The RD must retain knowledge and multiple skills, such as those discussed in this Highlight, to best care for their patients; these are sometimes referred to as enhanced or multiskilling in the dietetics practice. Suggest additional solutions for the digestive problems outlined in Highlight 3 that were not covered. Also suggest other areas that are not normally considered part of dietetics education that may enhance the practice role of dietitians and increase the visibility of their practice and the profession.

W H A T O T H E R R E S O U R C E S A R E A V A I L A B L E ?

You can look up information about government policy as well as any health condition that you are interested in learning more about. Consult the following websites to get reliable information on the following:

• Learn about nutrients by exploring information posted online: http://www.healthycanadians.gc.ca/camp/dvvqeng.php

• Learn about the latest research in nutrition or access resources for dietitians and other healthcare professionals at Dietitians of Canada: http://www.dietitians.ca

• Find out more about the nutritional needs of individuals living with diabetes at the Canadian Diabetes Association: http://www.diabetes.ca

• Find out more about the role of fibre and regulation of fat intake in the prevention of cardiovascular disease at the Heart and Stroke Foundation of Canada: http://www.heartandstroke.ca


http://heartandstroke.ca/

http://www.diabetes.ca/

http://www.dietitians.ca/

http://www.healthycanadians.gc.ca/camp/dv-vq-eng.php


• You can learn more about protecting and enhancing the health of your digestive system and digestive disorders at the Canadian Digestive Health Foundation: http://www.cdhf.ca

• The Canadian Society of Intestinal Research provides information on digestive diseases and other disorders at the Gastrointestinal Society: http://www.badgut.ca

A N S W E R K E Y F O R A L L I N S T R U C T O R ’ S M A N U A L A C T I V I T I E S

Critical Thinking Questions3

These questions will also be posted to the book’s website so that students can complete them online and email their answers to you.

1. Answer: In this question, look for students to use the information from the chapter to make an educated guess as to how anatomy and physiology will impact nutrient and nutritional status.

Painful and Bleeding Mouth Ulcers: This patient is dealing with a painful medical problem at the beginning of the digestive tract that will result in the patient’s inability to consume any food or liquids. In this case, salivary glands can be impacted, taste buds of the tongue may be poorly functioning, and mastication cannot occur. Attempts to provide food to the patient can result in aspiration because the patient may have an impaired swallowing ability that results in the food going into the lungs via the trachea. Careful monitoring for aspiration is important, as well as securing external nutrition support until the ulcers have had some time to heal prior to oral nutrition support.

Stomach Cancer: A bolus of food has to be passed from the esophagus into the stomach through the esophageal sphincter. The stomach’s goal is to further reduce the bolus into a mass called chyme with the help of its gastric juices. This semiliquid substance is released a bit at a time from the lower stomach into the duodenum via the pyloric sphincter. Stomach muscles are extremely strong and include three types: circular, longitudinal, and diagonal muscles. Depending on the extent and detail of the cancer, the stomach’s actions of reducing this bolus can be inhibited, reducing if not preventing its ability to move food from the esophagus into the small intestine. Surgery may impact the abilities of the muscle groups, which can also impact or inhibit the stomach’s abilities and actions. Given the critical nature of this step, external nutritional support may be considered temporally.

Gallbladder Surgery and Removal: The gallbladder moves bile into the duodenum. Bile is produced in the liver. The function of bile is to put fat from the diet into a suspension so that the enzymes that degrade fat can break the fat molecules down for absorption. One component of bile is cholesterol. If an individual does have the gallbladder removed, generally it has no effect on nutritional intake/absorption, as the

3 Contributed by Kathleen Rourke.


http://www.badgut.ca/

http://www.cdhf.ca/


bile can be secreted directly into the small intestine. Some individuals may need to watch their intake of fat due to an individual sensitivity.

2. Answer: Vascular System: The vascular system transports nutrients to the cells through the blood after they have been fully digested and absorbed through the intestinal tract. While there are a variety of vascular issues that can and may occur, any situation that compromises the vascular system will compromise this system’s ability to transport nutrients to the cells of the body. When the vascular system deteriorates, less oxygen is circulated to the cells. The system is also less effective in transporting nutrients to the tissue cells. Peripheral tissues can die from chronically compromised vascular systems, and depending on the length of the illness or vascular compromise, tissue destruction may continue to spread.

Absorptive System: The absorptive system relates to the inner surface of the small intestine where nutrients move through the intestinal surface (villi), into the blood. This intricate system of villi, microvilli, crypts, goblet cells, enzymes, and pumps is responsible for selecting specific nutrients at specific points along the small intestine for absorption and circulation. Should these villi be destroyed by chemicals, disease, etc., the ability to absorb nutrients properly is impacted. Depending on the severity of the situation, the patient may need external nutritional support.

3. Answer: Homeostasis means to maintain the body condition at the same level of or within a narrow range for appropriate functioning. Homeo is within an organic environment and stasis is to maintain a static environment.

Hormones, which are mostly proteins, and the nervous system are needed within the GI system to maintain homeostasis. For example, enterogastrone is a hormone that inhibits the motility and secretions of the GI tract when the stomach is full. This is signalled by the nervous system. Reversely, gastrin starts the release of the fluid hydrochloric acid. Gastrin release is stimulated by the expansion of the stomach wall. The continuing release of HCl increases the acidity of the stomach environment, which eventually shuts off the release of the HCl and thus the release of gastrin. To balance the acidic environment of HCl in the stomach, as the chyme goes through the pyloric sphincter, secretin and cholecystokinin are released or secreted from the duodenal wall and intestinal wall, respectively, to provide for the release of bicarbonate juices. This system of checks and balances, or negative feedback, exists throughout the GI tract to regulate the environment of the GI tract. This system provides for a consistent environment or maintenance of homeostasis. The work of both the hormonal and the nervous systems is uniquely and intricately timed in a system called the negative feedback system.

In the negative feedback system, one system is turned on to begin a process such as the release of gastrin, which allows for the release of HCl in the stomach to provide for the appropriate acidic environment for the stomach. Once the environment reaches its appropriate pH (or temperature, fluid level, etc.) the system is shut off automatically to maintain the body in homeostasis.

4. Answer: The bacteria in the intestine are called microflora and help to digest



foodstuffs such as the dietary fibres and complex proteins in the intestine. They are very important in creating the homeostatic environment, which is critical to the normal functioning of the GI tract. GI bacteria are not only able to break down nutritional contents in preparation for absorption, but they are also able to produce small amounts of different vitamins. Unfortunately, these vitamins are not produced at a level to meet the body’s nutrient needs. Two that were once thought to be supplied only by the diet are vitamins K and B12. Vitamin K is given to young infants as it is critical for blood clotting. Although Vitamin K is still needed through diet, our bodies do help to take care of requirements for vitamin K over time. The vitamin K given to newborns is mainly for prophylactic purposes. In the case of vitamin B12, bacteria in the body are able to supply some of this vitamin, but the RD should continue to assess a vegetarian patient’s need, because the quantities supplied by the body are too small to meet needs.

Patients can add probiotics to their diet, which can help to support the body’s natural bacterial flora. An example of a probiotic food is yogurt, which includes the nonharmful bacteria Lactobacillus. Probiotics help to support the intestinal environment, especially when a patient becomes ill with conditions such as diarrhea, inflammatory bowel disease, etc. Probiotics work with the normal bacterial flora to return the intestinal flora to its appropriate environment.

5. Answer: Patients free of medical health issues can still suffer from digestive problems through poor lifestyle choices or conditions. Our lifestyles are stressful; many individuals commute long distances to work or work many different jobs, and some have no job and worry about where their next meal will come from. Exercise habits are not always optimal, and many individuals complain of problems sleeping. In addition, issues with noise pollution as well as environmental pollution further stress the human condition. Assessment of a patient’s work habits, home environment, and exercise habits is important to the overall assessment profile for any patient. Patients who are able to find a way to positively and appropriately release stress remove stress hormones from their bodies. These hormones can have a broad and negative impact on the GI system as well as several other systems of the human body. One good stressrelease technique is exercise, which also helps to maintain the body’s musculature. Individuals that are stressed frequently suffer from digestive upsets or may turn to overeating as a relief to stress. Clearly, individuals must work, yet if the RD can find suggestions for the patient that would allow him or her to integrate exercise, stress management, and networking into work patterns as well as select healthy food choices, these tools will certainly optimize the patient’s health and wellbeing.

6. Answer: Highlight 3 does an excellent job of reviewing some of the common digestive problems that many patients will experience at some point in their lifetime. Most often, patients look to their physician or nurse for a solution. However, there is no reason that the registered dietitian cannot provide many of the same as well as many more effective solutions to the same common digestive problems. As the practice of dietetics grows, it will be important for the RD to grow their skill base and/or pursue advanced practice skills in an effort to provide the level of care



required by the patient population base. One excellent example at a very basic level is basic first aid. For a healthcare provider in a community setting, basic first aid skills are an important complement to practise skills.

Choking: In any situation where an individual has a potential airway problem, it is important to prevent further airway obstruction and provide oxygen if it can be accessed. When an individual under your care has had an airway problem, it is also important not to give any further foods or liquids through the airway until the individual is fully assessed by medical personnel. This is especially important in the event that a stroke or any other abnormal event is considered to have caused the airway obstruction in the first place.

Vomiting: As indicated, there are many reasons for vomiting. What is important to observe with the vomiting patient is their hydration status. For appropriate age groups (teen and young adult), assess for eating disorders. As indicated, in babies and in the elderly, excessive vomiting can be very serious. In both of these populations, excessive fluid losses can lead to deadly electrolyte imbalances very quickly. Therefore, both the very young and the very elderly should be transported to a medical facility quickly in these circumstances.

Any young or middleaged adult who is assessed for an eating disorder (by teeth erosion, mouth sores, etc.) should be referred to a psychologist or an agency that can provide appropriate support for psychological counselling.

Always assess a patient’s skin tone for its turgor, or ability to bounce back when pinched gently. This can inform the practitioner whether the patient is well hydrated. When the practitioner gently grasps a small amount of skin from the side of the abdomen or the wrist and the skin immediately falls back into place, the tone is good and hydration is also good. If the skin is slow to respond, hydration is poor and further assessments should be made.

If there is no medical or physical rationale for the vomiting and the patient is an adult who is suffering from vomiting from a stomach virus, a teaspoon of cola syrup can be effective in calming the stomach for a period of time. This treatment can be used across the age groups but should only be used after it is approved by a medical practitioner.

Diarrhea: Like vomiting, diarrhea can result in dehydration and for many reasons. The goal is always to find the cause of diarrhea prior to intervening. Slowing down the transit of nutrients through the GI tract is important for their absorption; therefore, it is very important to control diarrhea when medically possible. After a patient has been cleared of any medical issues, it is important to remember that the GI tract can be very sensitive to the individual’s stress. It is important to assist patients in relaxing through their medical procedures and to keep them as fully informed as possible. Patients can benefit from counselling, stress management training, and relaxation therapy. Dietitians who are not trained in these skills should keep a listing of local professionals to refer their patients to when needed.

Constipation: Like diarrhea, this can be a result of stress or may result from mechanical or other issues. The RD must focus on the diet and make sure that the



fibre content is adequate for elimination. Many Canadians do not eat enough fibre and many medications complicate the issue further. Adding fibre to the diet can significantly improve many individuals’ elimination issues. Exercise is equally important in optimizing elimination issues. Finally, plenty of fresh water with a highfibre diet and exercise will solve most individuals’ constipation issues.

Belching and Gas: Given that the RD is recommending a diet with plenty of fruits, vegetables, and legumes, it is no wonder that individuals have gas. However, there are many products on the market that help to deal with this issue, including Beano, Lactaid for those that have lactose intolerance, etc. Make patients aware of the products that can help them after fully assessing their physical and medical issues.

Not only does the product market continually expand for patients, for whom the RD must keep up to date, but patients experience plenty of stress in our presentday economy. The RD is smart to do a thorough assessment on each patient and seek every option for healthcare support. Among these options, exercise, stress management training, advocate training, and selfawareness programs assist the patients in optimizing their health and better aligning their expectations with the healthcare provider’s.

Worksheet Answer KeyWorksheet 31Table: promote; promote; impede; impede; promote; impede; impede; impede; impede. 1., 2. Answers will vary.



Worksheet 32

E C

P E S O P H A G U S

I L T

G O O

L A P P E N D I X M

O A A

T N C

T C H

L I V E R T

S E R

G A L L B L A D D E R

S C

H

D U O D E N U M

A



W O R K S H E E T A C T I V I T I E S

Worksheet 31: Digestion and Absorption

Identify which of these foods and food habits promote or impede healthy digestion and absorption.

Foods and Food Habits Promote Impede

Take small bites of food.

Chew thoroughly before swallowing.

Exercise immediately after eating to prevent weight gain.

Eat a lowfibre diet.

Drink plenty of fluids.

Eat a few large meals instead of several smaller ones.

Eat quickly and then lie down to rest.

Create a meal using citrus fruits and meat.

Tackle family problems at the dinner table.

1. Do you experience GI distress regularly?

2. What changes can you make in your eating habits to promote GI health?



Worksheet 32: Chapter 3 Crossword Puzzle

1 2

3 4

5 6

7 8

9

10

Across Down

3. The food pipe; the conduit from the mouth to the stomach

5. A narrow blind sac extending from the beginning of the colon; a vestigial organ with no known function

7. The organ that manufactures bile and is the first to receive nutrients from the intestines

9. The organ that stores and concentrates bile

10. The top portion of the intestine

1. Cartilage in the throat that guards the entrance to the trachea and prevents fluid or food from entering it when a person swallows

2. The lower portion of the intestine that completes the digestive process and consists of four segments

4. A muscular, elastic, saclike portion of the digestive tract that grinds and churns swallowed food

6. A gland that secretes digestive enzymes and juices into the duodenum

8. The windpipe

Contributed by Mary A. Wyandt



Handout 31: Transport of Nutrients into Blood

Nutrient Transport into Blood

Watersoluble NutrientsCarbohydratesMonosaccharides Directly into bloodLipidsGlycerolShortchain fatty acidsMediumchain fatty acids

Directly into bloodDirectly into bloodDirectly into blood

ProteinsAmino Acids Directly into bloodVitaminsVitamins B and C Directly into bloodMinerals Directly into blood

Fatsoluble NutrientsLipidsLongchain fatty acidsMonoglyceridesTriglyceridesCholesterolPhospholipids

Made into triglyceridesMade into triglyceridesTo lymph, then bloodTo lymph, then bloodTo lymph, then blood

VitaminsVitamins A, D, E, and K To lymph, then blood



Handout 32: Digestive Juices and Their Constituents

Site of Secretion pH Constituents

Site of Secretion pH Constituents

Mouth: salivaSalivary glands

6.8–7.2 MucinAmylase (ptyalin)

Pancreas 7.0–8.0 Thin, watery, alkaline, enzymepoor juiceAmylaseChymotrypsinogenChymotrypsinTrypsinogenTrypsinLipaseCarboxypeptidase

Stomach: gastric juiceParietal cells

Renin (infants)

2.0–2.5 HClPepsinogenPepsinMucinLipaseIntrinsic factor

Liver: bile 6.9–8.6 Bile saltsBile acidsBile pigmentsCholesterolMucin

Small intestine 7.0–8.0 EnterokinaseAminopeptidaseDipeptidaseNucleinaseNucleotidaseLecithinaseSucraseMaltaseLactase



Handout 33: Where the Foods Are Broken Down

Location & MoleculesCracker

(Carbohydrates) Peanuts (Proteins)A Pat of Butter

(Lipids)

Mouth (salivary amylase and lingual lipase)

• Starches into oligosaccharides

• Just peanut proteins and saliva

• Triglycerides and a few saturated fatty acids

Esophagus • Just passes through • Just passes through • Just passes through

Stomach (hydrochloric acid and gastric lipase)

• Just sloshes along • Proteins get scrambled (denatured)

• Smaller polypeptides appear

• Still triglycerides and a few saturated fatty acids

Small Intestine (lipases, sucrase, maltase, lactase, proteases, and trypsin)

From the pancreas: lipases, sucrase, maltase, lactase, proteases, and trypsin

• Starches are broken down into disaccharides and then into monosaccharides

• Smaller polypeptides are broken down into di and tripeptides and then into single amino acids

• Triglycerides are broken down into saturated fatty acids and glycerol

Large Intestinal Cells • Water and some minerals are absorbed into the bloodstream and the rest is eliminated

• Water is absorbed into the bloodstream and the rest is eliminated

• Any remaining foodstuffs are eliminated

Contributed by Mary Ellen Clark



Handout 34: Heartburn—How to Deal With It?

Other names • Acid reflux • Gastroesophageal reflux disease (GERD)

What is it? • Splashing of acidic stomach contents back into the esophagus, which can irritate the delicate lining of the esophagus and cause a burning pain between the throat and chest.

• It can cause a cough, a sore throat, difficulty swallowing, or bad breath in some people.

When is it a problem? • Symptoms that recur one or more times a week should be discussed with a healthcare provider.

What causes it? • The sphincter between the stomach and esophagus can loosen and allow stomach contents to leak upward into the esophagus.

• Some people’s stomachs produce too much acid, which can also splash up into the esophagus. Triggers like stress, caffeine, smoking, alcohol, chocolate, greasy foods, or spicy foods can cause symptoms in some people, but not the same triggers bother everyone.

What happens if it is left untreated?

• The cells of the esophagus can undergo some changes due to the chronic irritation of longterm, untreated GERD. In a small percentage of people, these abnormal cells may become cancerous.

• The person suffers repeated bouts of pain if the condition is not treated. This can seriously affect one’s lifestyle and appreciation of food/drink.

Treatment Options for HeartburnLifestyle Changes Major Types of Medicines

• Sit up after eating so that the stomach contents cannot leak back into the esophagus

• Lose excess weight, which may be associated with a looser esophageal sphincter

• Find out what foods trigger pain. Eliminate one food at a time to see if symptoms become less frequent or severe

• Eat smaller meals, which may not expand the stomach as much

• Wear loser clothing which will not squeeze the stomach and push its contents back through the esophageal sphincter

• Quit smoking, which may trigger the stomach to secrete more acid or may weaken the esophageal sphincter

• Antacids like Tums, Rolaids, or Maalox have minerals like calcium, magnesium, or aluminum to neutralize stomach acid

• Acidblockers such as Pepcid, Tagamet, or Zantac reduce the amount of acid that the stomach produces

• Protonpump inhibitors such as Prilosec and Prevacid reduce stomach acid more than acid blockers

• Foaming agents such as Gaviscon which coats the surface of the stomach

What works best? Lifestyle or medicine approaches? Actually, a combination of both approaches works the best for many people! Some people find that they can take medicine for shorter periods of time if they also incorporate some simple lifestyle changes. Others may be able to stop taking medicine, especially if they discover which foods or situations trigger heartburn.

References: Dr. Andrew Weil's Self Healing, June 2004, pp. 4–5; Nutrition Action Health Letter, Gut Check, Volume 30 (3), April 2003 , pp. 3–4.

Contributed by Mary Ellen Clark


Documents

Chapter 3 Digestion, Absorption, and Transports3.amazonaws.com/prealliance_oneclass_sample/roVRBea0vJ.pdf · Diseases involving carbohydrate metabolism ... the breakdown of some carbohydrates